# NTSB ATL91IA014: Bell 412, N412UT, Knoxville, TN, November 3, 1990

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: November 2, 1990, 21:25 local (Nov 3, 1990, 02:25 UTC)
- Place: Knoxville, TN
- Coordinates: 36.059787, -83.920944 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=36.0598&lon=-83.9209&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 4 uninjured
- Status: Completed, report December 30, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 8339
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL91IA014
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8339/pdf
- Page: https://openairdocs.org/ntsb/ATL91IA014

## Probable cause

THE PILOT'S FAILURE TO SEE AND AVOID THE WIRES PRIOR TO THE COLLISION. FACTORS IN THE INCIDENT WERE THE FAILURE OF THE GROUND PERSONNEL TO ADEQUATELY INSPECT THE LANDING ZONE, THE PRESENCE OF HIGH INTENSITY LIGHTS AT THE LZ, AND THE DARK LIGHTING CONDITIONS.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- In flight collision with object, takeoff - initial climb
  - terrain condition - roadway/highway
  - light condition - dark night (contributing factor)
  - object - wire,transmission
  - visual lookout - inadequate, pilot in command (cause)
  - visual lookout - inadequate, ground personnel (contributing factor)

## Analysis

THE NIGHT, VFR FLIGHT WAS DISPATCHED TO A STRETCH OF INTERSTATE HIGHWAY TO PICK UP A PATIENT. PRIOR TO LANDING THE LZ WAS SEARCHED FOR OBSTRUCTIONS WITH THE 'NIGHT SUN', AND THE GROUND PERSONNEL ALSO INSPECTED THE LZ. NO OBSTRUCTIONS WERE REPORTED OR OBSERVED IN THE IMMEDIATE LZ AREA. AFTER LANDING, THE PILOT ALSO WALKED THE DEPARTURE CORRIDOR WITH A FLASHLIGHT. SHORTLY AFTER TAKEOFF, THE HELICOPTER COLLIDED WITH FOUR WIRES WHICH WERE STRUNG ACROSS THE HIGHWAY. NEITHER THE FLIGHT CREW NOR THE GROUND PERSONNEL SAW THE WIRES PRIOR TO THE COLLISION. THE WIRES WERE BLACK IN COLOR, AND THE POLES WERE HIDDEN BY BUILDINGS AND TREES. ALSO, HIGH INTENSITY LIGHT STANDARDS LINED THE HIGHWAY AT THE LZ.

## Aircraft

- Registration: N412UT (not matched to a registry record)
- Reported make and model: BELL 412
- Category: Helicopter
- Serial number: 33025
- Engines: P&W PT6T-3B 1800 horsepower turbo shaft
- Damage: Minor damage
- Flight: Part 135
- Registered owner: University Of Tennessee

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; toxicology performed; flight hours: 6,278 total, 556 in this make and model, 4,812 as pilot in command, 60 in the last 90 days, 20 in the last 30 days

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F
- Observed at: TYS

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Incident 19901102048589I](https://openairdocs.org/incident/19901102048589I), Nov 2, 1990: Bell 412, Knoxville, TN. Struck unseen wires on medic flight after liftoff from freeway. Landed safely. Power poles hidden by trees,building

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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